Burglar-alarm.



UNITED STATES PATENT orrroa.

' WILLIAM E. CLARK, orsamac LAKE, NEW yoax.

Specification of Letters Patent.

Patented June 30, 1914.

Application tlled August 18. 1912. Serial N 0. 715,447.

To all whom it may concern:

Be itknown that I, WILLIAM citizen of the United States, anac Lake, inthe county of Franklin and State of New York, have invented certain newand useful Improvements in. Burglar- Alarms, of which the following isa. specification.

-My invention relates to new and useful improvements in burglar alarmsand more reven-ting safe breaking in post-offices, st res and other likeplaces.

E. CLARK,

. The invention, is hereinafter described with reference to theaccompanying draw- 1 ln the drawing: Figure 1 is a longitudinalsectional View, showing my alarm in position, the wiring being showndiagrammatically; Fig. ,2 is a fragmentary detail sectional view,showing the construction of one of the circuit closers; Figs, 3 and 4are top lan views, showi'ngthe movable board or p atform which closesthe circuits when depressed by the weight of a person'stepping orstanding upon thesame; Fig. 5 is a diagrammatic view of the wiring ofthe alarm,

Corresponding and like parts are referred to in the followingdescription and indicated in all the views of the drawing by the samereference characters.

The preferred embodiment of my invention primarily includes a movableboard or platform, designated as a Whole by the numeral 10 and replacingone or more boards in the floor immediately in front of the safe orother property to be protected, an electrically operated alarm devicesuch as a bell 11, circuit closers 12 so positioned as to be operatedby. the depression of the board or platform 10, and a plurality ofcircuits 13 connected between the circuit closers and alarm.

More specifically, one of the boards of the floor 14: 1s removed andadjacent floor timbers 15 are provided in their upper faces withrecesses 16 below the opening in the floor thus. formed and the circuitclosers 12 are seated in these recesses with their upper facessubstantially flush with the upper face of the floor timbers. Theopening in the fioor is then closed by means of the board 10 which isprovided at either end with a downwardly projecting pin 17 which engagesthe movable members of the circuit closers, the boardbein residing atSar-' thereby supported a slight distance above t .e level of the floor.

Each circuit closer includes an insulating I base 18 carrying a fixedcontact 19 and a movable contact 20, the latter consisting of a springarm which spaced relation above the contact 19.- The base member 18carries a casing 21 and mounted through an opening formed in the top ofthis casing, is a plunger 22, the inner end of which engages against theupper face of the contact member 20, while the outer end extendssubstantially flush with the top of the casing which is depressedcentrally as "shown. I

The pin 17, previously mentioned, is preferably as shown at 23 and hasits outer end provided with a screw driver receiving slot '24 by meansof which it may be threaded into the lower face of the board. Because ofthis, the pin may be readily adjusted to space its free end in anydesired distance below in such a manner that w en the board is depressedit will act upon the plunger 22 to move t e contact 20 into engagementwith the contact 19 at exactly the same time that the board seats uponthe floor timbers at either side of the recess. By careful adjustment ofthe various parts, the circuit closer and its operating pin 1? ma be soarranged that the board 10 need on y move through a small fraction of aninch to close the circuit, thereby permitting the board to lie almostflush with the surface of the floor and therefore be unnoticeable. Thecircuit closers are arranged one beneath each end of the board in orderto insure the closing of a circuit by the depression of the board, eventhough the weight applied upon the same is wholly at one end. In Fig. 3of the drawing, 1 have illust-rated a slightly modified form ofconstruc-.

tion in which several boards are removed from the floor 14 and replacedby a platform composed of a plurality of boards 25 which may be ofdifi'erent lengths to conform to the manner in which the floor boardsare laid and which are secured adjacent their ends to transverselyextending cleats or braces 26. In this case, the circuit closers arepositioned one under each end of each of these cleats and the pins areof course carried by the cleats and so positioned as to en.- gage'withthe circuit closers.

normally extends in The wiring of my improved alarm is very simple. Anelectric bell or other suitable signaling device 11 is positioned at anysuitable point such as in the janitors room, or even in the policestation and one terminal of thisbell is connected by a wire 27 with oneterminal of a battery 28. A plu-' rality of wires 29 connect theopposite terminal of the battery with the contact members 19 of thecircuit closers. Positioned in a convenient place near the bell 11 is aswitch including a switch blade 30 swingingly mounted by one end upon acontact member 31 and adapted to be moved in and out of engagement witha second contact 32. A wire 33 connects the free terminal of the bell 11with-the contact 31, while wires 34 connect the contact 32 with themovable contacts 20 of the circuit closers.

From the foregoing description, the operation of my alarm will be readilunderstood. In the daytime or at any 0t er time when the alarm is not inuse, the switch blade 30 may be swung to open all circuits to the bellbut at other times this switch will be closed. The board or platform 10is preferably positioned immediately in front of the safe in such amanner that any one tampering with the safe will be sure to step upon itand depress it to close one or more of the circuit closers to give thealarm. As. clearly shown in the drawing I have provided an entirelyseparate and distinct cir-' cuit between each or the circuit closers andthe bell and in practice the wires of these 1,10 ace circuits arepreferably run through difierentparts of the building so that eventhough a safe breaker discovers and cuts certain of the wires, theremaining circuits will remain operative.

It will of course be understood that I do not wish in any way to limitmyself to the.

application of this alarm as a protection for safes or any otherparticular ropert-y as it may be employed as a general burglar alarm inhouses, the movable board or platform bein positioned at any suitablepoint as in the all or one of the steps of a flight of stairs.

Having thus described the invention, what is claimed as new is: i

A burglar alarm including a movable floor section, a plurality of pinscarried by the floor section and adjustable therein, a plurality ofcircuit closers carried by thefiloor timbers and each including anoperating plunger, the circuit closers being so arranged that each ofthe pins carried by the floor section engages one of the plungers, anelectric signaling device, a plurality of energized circuits connectingthe circuit closers and signaling device, and a switch arranged to openand close all of said circuits.

In testimony whereof I afiix my signature in presence of two witnesses.

WILLIAM E. CLARK.

